<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>单侧投影</title>
    <link rel="stylesheet" href="../public.css">
    <style>
        .shadow {
            width: 100px;
            height: 100px;
            margin: 20px auto;
            background-color: khaki;
            box-shadow: 0px 9px 8px -8px red;
            /* box-shadow: 0 5px 4px -4px black; */
        }

        .box {
            width: 100px;
            height: 100px;
            margin: 20px auto;
            background-color: khaki;
        }

        .shadow1 {
            box-shadow: 3px 3px 6px -3px black;
        }
        .shadow2{
            box-shadow: 8px 0 6px -6px red,
                        -8px 0 6px -6px red;
        }
    </style>
</head>

<body>
    <div class="content">
        <h1>单侧投影</h1>
        <ul>
            <li>box-shadow:2px 3px 4px rgba(0,0,0,.5)</li>
            <li>以该元素相同的尺寸和位置，画一个rgba(0,0,0.5)的矩形</li>
            <li>把它右移2px，向下3px</li>
            <li>使用高斯模糊算法，将他进行4px的模糊处理</li>
            <li>模糊后的矩形与原始元素交集部分会被切除掉</li>
        </ul>
        <div class=" trapezoid ">
            <div class="">
                <img src="../03视觉效果/img/box-shadow.png" alt="">
                <ul>
                    <li>利用扩张半径，这个参数会根据你指定的值去扩大或缩小投影的尺寸</li>
                    <li>box-shadow: 0px 9px 8px -8px red;</li>
                </ul>
                <div class="shadow">

                </div>
            </div>
        </div>
    </div>
    <div class="content">
        <h1>邻边投影</h1>
        <ul>
            <li>扩张值为模糊半径的一半</li>
            <li>水平和垂直方向上的移动的值需要大于或者等于模糊半径的一半</li>
        </ul>
        <div class="box shadow1 ">
        </div>
    </div>
    <div class="content">
        <h1>两侧投影</h1>
        <ul>
            <li>单边投影应用两次</li>
        </ul>
        <div class="box shadow2 ">
        </div>
    </div>
</body>

</html>